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Abstract

Prior to the discovery of medical treatment for diabetes, carbohydrate-restriction
was the predominant treatment recommendation to treat diabetes mellitus. In this commentary
we argue that carbohydrate-restriction should be reincorporated into contemporary
treatment studies for diabetes mellitus.

Introduction

In the early 20th century, before any medications were available for the treatment of diabetes mellitus,
experts recommended dietary carbohydrate-restriction [1,2]. The dietary recommendation for diabetes in a prominent internal medicine textbook
from 1923 was 75% fat, 17% protein, 6% alcohol and only 2% carbohydrate [3]. The recommended total daily energy intake was 1,795 Calories per day. After the
discovery of insulin and oral hypoglycemic medications, experts gradually changed
the dietary recommendations to include more carbohydrate intake because most experts
reasoned that the medications could be used to keep the glucose in control.

The NIH NHLBI Action to Control Cardiovascular Risk in Diabetes (ACCORD) group recently
announced termination of the intensive insulin therapy arm of their study after an
interim analysis showed that mortality was significantly higher in this group than
in the other two less intensive glucose control groups [4,5]. Because lead investigators from the ACCORD trial and other experts have stated how
unexpected this finding was, and have suggested that the concept of normal glucose
control among patients with type 2 diabetes may not be desirable, we feel compelled
to provide an alternative view.

Discussion

From our perspective of familiarity with dietary carbohydrate-restriction and diabetes,
these results are not surprising–in fact, they are predicted. We believe that it is
unlikely that the increased mortality was due to the tight glucose control but rather
due to the particular method for trying to achieve it. When high carbohydrate diets are consumed and intensive medication therapy is used to "cover the carbohydrate,"
it is very difficult to achieve normal glycemic control without hypoglycemic reactions. In our clinical practices, we frequently see individuals who are instructed to eat
high carbohydrate diets and use intensive injectable hypoglycemic therapy, and they
are susceptible to hypoglycemic reactions. Severe hypoglycemic reactions are associated
with an increased morbidity and mortality [6].

There are other ways to improve glycemic control without the risk of hypoglycemic
reactions; one of these is carbohydrate-restriction. Carbohydrate-restriction makes
pathophysiological sense because type 2 diabetes is, in essence, a case of carbohydrate intolerance. We have observed that the same patients who have hypoglycemic reactions with high
carbohydrate diets and aggressive medication therapy no longer have hypoglycemic reactions
with carbohydrate-restriction. Moreover, the continued concerns about carbohydrate-restricted
diets have never materialized and recent scientific studies show general health benefits
including reduced cardiometabolic risk factors [7-10].

Based on the clinical experience of others, and published clinical trials, we use
carbohydrate-restriction in clinical practice for the treatment of diabetes mellitus
[11-15]. At the end of our clinic day, we go home thinking, "The clinical improvements are
so large and obvious, why don't other doctors understand?" Carbohydrate-restriction
is easily grasped by patients: because carbohydrates in the diet raise the blood glucose,
and as diabetes is defined by high blood glucose, it makes sense to lower the carbohydrate
in the diet. By reducing the carbohydrate in the diet, we have been able to taper
patients off as much as 150 units of insulin per day in 8 days, with marked improvement
in glycemic control-even normalization of glycemic parameters. Due to the potent effect
of carbohydrate restriction in decreasing blood glucose levels, we must reduce the
insulin by 50% on the first day of dietary carbohydrate-restriction to avoid hypoglycemia.
As the weeks pass, most patients achieve normoglycemia without medication, obese patients
lose weight, and patients save money because they are not paying for medications.
It is not so far-fetched to predict that these savings will also be passed along to
the health care system and self-insured companies because there will be less expenditure
on medications and the long-term diabetic complications.

Conclusion

The inattention to potent dietary therapy in all recent major diabetes studies, including the recent ACCORD
trial, should not lead us to forget about carbohydrate-restriction as a means to achieve
weight loss and glycemic control without hypoglycemia. We urgently need controlled
studies comparing the newer "higher-carbohydrate diet with or without medication"
approach to the earlier "carbohydrate-restricted diet without medication" approach
for type 2 diabetes mellitus. One of the important advantages of carbohydrate-restriction
is that there is no risk of hypoglycemia if medications are not used. We believe that carbohydrate-restriction
has come of age for the treatment of obesity and diabetes mellitus and should be urgently
translated from clinical practice to intensive testing in studies relating to mechanism,
health services research, and public health.

Competing interests

ECW has received unrestricted research grant funding from the Robert C. Atkins Foundation.
MCV has written a book about the treatment of diabetes with carbohydrate-restriction.